The MiniBooNE experiment at Fermilab reports results from a search for $\bar
\nu_\mu \rightarrow \bar \nu_e$ oscillations, using a data sample corresponding
to $5.66 \times 10^{20}$ protons on target. An excess of $20.9 \pm 14.0$ events
is observed in the energy range $475<E_\nu^{QE}<1250$ MeV, which, when
constrained by the observed $\bar \nu_\mu$ events, has a probability for
consistency with the background-only hypothesis of 0.5\%. On the other hand,
fitting for $\bar{\nu}_{\mu}\rightarrow\bar{\nu}_e$ oscillations, the best-fit
point has a $\chi^2$-probability of 8.7\%. The data are consistent with $\bar
\nu_\mu \rightarrow \bar \nu_e$ oscillations in the 0.1 to 1.0 eV$^2$ $\Delta
m^2$ range and with the evidence for antineutrino oscillations from the Liquid
Scintillator Neutrino Detector at Los Alamos National Laboratory.

I nearly missed this due to its understated title and abstract that don't even allude to the possible cosmological significance, but this could be very interesting for cosmology if sterile neutrinos could be dark matter.

In 2007 MiniBooNE announced their oscillation results from a neutrino beam were not consistent with LSND, which disfavored sterile neutrinos. But recently (well, last summer, but I am a bit behind on particle physics news, apparently) they announced results using an antineutrino beam that DO support the LSND results. Maybe there are sterile neutrinos after all?

I don't think the case is rock-solid yet, but we cosmologists should definitely be paying attention to this!